DTC DETECTION LOGIC
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crankshaft position (CKP) sensor (POS) signal to vary, ECM can determine that a misfire is occurring.

The misfire detection logic consists of the following two conditions.

One Trip Detection Logic (Three Way Catalyst Damage) On the 1st trip, when a misfire condition occurs that can damage the three way catalyst (TWC) due to overheating, the MIL will blink.

When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.

Two Trip Detection Logic (Exhaust quality deterioration) For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only illuminate when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sensor signal every 1,000 engine revolutions.

A misfire malfunction can be detected in any one cylinder or in multiple cylinders.

DTC CONFIRMATION PROCEDURE1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.

Start engine and drive the vehicle under similar conditions to (1st trip) Freeze Frame Data for a certain time. Refer to the table below. Hold the accelerator pedal as steady as possible.

Similar conditions to (1st trip) Freeze Frame Data mean that the following conditions should be satisfied at the same time.

CAUTION:Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when driving.

Driving time varies according to the engine speed in the freeze frame data.

Check 1st trip DTC. Is 1st trip DTC detected?

YES >> Go to Diagnosis Procedure.
NO >> Inspection END

Diagnosis Procedure1.CHECK FOR INTAKE AIR LEAKAGE AND PCV HOSE

Start engine and run it at idle speed.

Listen for the sound of the intake air leakage.

Check PCV hose connection. Is intake air leakage detected?

YES >> Discover air leakage location and repair.
NO >> GO TO 2.2.CHECK FOR EXHAUST SYSTEM CLOGGING
Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
Is the Inspection result normal?
YES-1 >> With CONSULT-III: GO TO 3.
YES-2 >> Without CONSULT-III: GO TO 4.
NO >> Repair or replace malfunctioning part.3.PERFORM POWER BALANCE TESTWith CONSULT-III

Start engine.

Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT-III.

Check that each circuit produces a momentary engine speed drop. Is the Inspection result normal?

CAUTION:Perform the following procedure in a place with no combustible objects and good ventilation.

Turn ignition switch OFF.

Remove fuel pump fuse in IPDM E/R to release fuel pressure.

NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following procedure.

Start engine.

After engine stalls, crank it 2 or 3 times to release all fuel pressure.

Turn ignition switch OFF.

Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.

Remove ignition coil and spark plug of the cylinder to be checked.

Crank engine for 5 seconds or more to remove combustion gas in the cylinder.

Connect spark plug and harness connector to ignition coil.

Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 -0.66 in) between the edge of the spark plug and grounded metal portion as shown in the figure.

Crank engine for approximately 3 seconds, and check whether spark is generated between the spark plug and the grounded metal portion.

Spark should be generated.

CAUTION:

Never place the spark plug and the ignition coil within 50 cm (19.7 in) each other. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.

It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.

NOTE:When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunctioning.
Is the Inspection result normal?
YES >> GO TO 9.
NO >> GO TO 6.6.CHECK FUNCTION OF IGNITION COIL-II

Turn ignition switch OFF.

Disconnect spark plug and connect a non-malfunctioning spark plug.

Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.

Also check harness for short to power. Is the Inspection result normal?

YES >> GO TO 14.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.14.CHECK A/F SENSOR 1 HEATER
Refer to See: P0031.
Is the Inspection result normal?
YES >> GO TO 15.
NO >> Replace malfunctioning A/F sensor 1.15.CHECK MASS AIR FLOW SENSORWith CONSULT-III